1. Field of the Invention
The invention relates to a semiconductor device including a thick film electrode and a method for manufacturing the same.
2. Background Art
Electrode films are being thickened to accompany the increased currents and the increased operation speeds of semiconductor devices. The electrode portions of such semiconductor devices are formed in stacked structures by sputtering. In the case where film thickening of the electrode portions is performed, the electrode portions are formed using rerouting technology after chip formation (for example, refer to JP-A 2003-23236 (Kokai)).
Therefore, a rerouting process is necessary after completion of the manufacturing processes of the semiconductor chip, which leads to an increase of the manufacturing processes. Moreover, such rerouting technology makes openings by patterning an insulating film provided on the semiconductor, and continuous interconnects are formed in the openings. Because the insulating film is subsequently removed, unstable (easily reacting activation) metal is exposed at the side wall portions of the rerouting portion, is susceptible to corrosion due to moisture and the like in air; and there is a risk of reduced reliability. Further, in the case where the foundation is patterned in this state, the unstable (easily reacting activation) metal of the side faces corrodes.
Therefore, it has also been proposed to form a thick film of copper (Cu) and form a covering film of gold (Au) by surface plating around the copper (Cu) (for example, refer to JP-A 2000-150518 (Kokai)).